The Transtheoretical Model of Behavior Change assesses an individual's readiness to act on a new healthier behavior, and provides strategies, or processes of change to guide the individual through the stages of change to Action and Maintenance in behavior change.

The Transtheoretical Model is also known by the abbreviation "TTM"[1] and by the term "stages of change."[2][3] A popular book, Changing for Good,[4] and articles in the news media[5][6][7][8][9] have discussed the model. It is "arguably the dominant model of health behaviour change, having received unprecedented research attention, yet it has simultaneously attracted criticism."[10]

Prochaska and colleagues refined the model on the basis of research that they published in peer-reviewed journals and books.[13][14][15][16][17][18][19][20][21][22][23][24][25][26] The model consists of four "core constructs": "stages of change," "processes of change," "decisional balance," and "self-efficacy."[25]

People at this stage do not intend to start the healthy behavior in the near future (within 6 months), and may be unaware of the need to change. People here learn more about healthy behavior: they are encouraged to think about the pros of changing their behavior and to feel emotions about the effects of their negative behavior on others.

Precontemplators typically underestimate the pros of changing, overestimate the cons, and often are not aware of making such mistakes.

One of the most effective steps that others can help with at this stage is to encourage them to become more mindful of their decision making and more conscious of the multiple benefits of changing an unhealthy behavior.

Stage 2: Contemplation (Getting Ready)
At this stage, participants are intending to start the healthy behavior within the next 6 months. While they are usually now more aware of the pros of changing, their cons are about equal to their Pros. This ambivalence about changing can cause them to keep putting off taking action.

People here learn about the kind of person they could be if they changed their behavior and learn more from people who behave in healthy ways.

Others can influence and help effectively at this stage by encouraging them to work at reducing the cons of changing their behavior.

Stage 3: Preparation (Ready)
People at this stage are ready to start taking action within the next 30 days. They take small steps that they believe can help them make the healthy behavior a part of their lives. For example, they tell their friends and family that they want to change their behavior.

People in this stage should be encouraged to seek support from friends they trust, tell people about their plan to change the way they act, and think about how they would feel if they behaved in a healthier way. Their number one concern is: when they act, will they fail? They learn that the better prepared they are, the more likely they are to keep progressing.

Stage 4: Action
People at this stage have changed their behavior within the last 6 months and need to work hard to keep moving ahead. These participants need to learn how to strengthen their commitments to change and to fight urges to slip back.

People in this stage progress by being taught techniques for keeping up their commitments such as substituting activities related to the unhealthy behavior with positive ones, rewarding themselves for taking steps toward changing, and avoiding people and situations that tempt them to behave in unhealthy ways.

Stage 5: Maintenance
People at this stage changed their behavior more than 6 months ago. It is important for people in this stage to be aware of situations that may tempt them to slip back into doing the unhealthy behavior—particularly stressful situations.

It is recommended that people in this stage seek support from and talk with people whom they trust, spend time with people who behave in healthy ways, and remember to engage in healthy activities to cope with stress instead of relying on unhealthy behavior.

To progress through the early stages, people apply cognitive, affective, and evaluative processes. As people move toward Action and Maintenance, they rely more on commitments, conditioning, contingencies, environmental controls, and support.[29]

Prochaska and colleagues state that their research related to the Transtheoretical Model shows that interventions to change behavior are more effective if they are "stage-matched," that is, "matched to each individual's stage of change."[25][nb 4]

This core construct "reflects the individual's relative weighing of the pros and cons of changing."[25][nb 5] Decision making was conceptualized by Janis and Mann as a "decisional balance sheet" of comparative potential gains and losses."[30] Decisional balance measures, the pros and the cons, have become critical constructs in the Transtheoretical Model. The pros and cons combine to form a decisional "balance sheet" of comparative potential gains and losses. The balance between the pros and cons varies depending on which stage of change the individual is in.

Sound decision making requires the consideration of the potential benefits (pros) and costs (cons) associated with a behavior's consequences. Decisional balance is one of the best predictors of future change. TTM research has found the following relationships between the pros, cons, and the stage of change across 48 behaviors and over 100 populations studied.

This core construct is "the situation-specific confidence people have that they can cope with high-risk situations without relapsing to their unhealthy or high risk-habit."[25][nb 6] Self-efficacy[32] conceptualizes a person's perceived ability to perform on a task as a mediator of performance on future tasks. A change in the level of self-efficacy can predict a lasting change in behavior if there are adequate incentives and skills. The Transtheoretical Model employs an overall confidence score to assess an individual's self-efficacy. Situational temptations assess how tempted people are to engage in a problem behavior in a certain situation.

A national sample of pre-Action adults was provided Pro-Change’s Stress Management intervention. At the 18-month follow-up, a significantly larger proportion of the treatment group (62%) was effectively managing their stress when compared to the control group. The intervention also produced statistically significant reductions in stress and depression and an increase in the use of stress management techniques when compared to the control group.[33]

Over 1,000 members of a New England group practice who were prescribed antihypertensive medication participated in Pro-Change’s Adherence to Antihypertensive Medication intervention. The vast majority (73%) of the intervention group who were previously pre-Action were adhering to their prescribed medication regimen at the 12-month follow-up when compared to the control group.[34]

Members of a large New England health plan and various employer groups who were prescribed a cholesterol lowering medication participated in Pro-Change’s Adherence to Lipid-Lowering Drugs intervention. More than half of the intervention group (56%) who were previously pre-Action were adhering to their prescribed medication regimen at the 18-month follow-up. Additionally, only 15% of those in the intervention group who were already in Action or Maintenance relapsed into poor medication adherence compared to 45% of the controls. Further, participants who were at risk for physical activity and unhealthy diet were given only stage-based guidance. The treatment group doubled the control group in the percentage in Action or Maintenance at 18 months for physical activity (45%) and diet (25%).[35]

Participants were 350 primary care patients experiencing at least mild depression but not involved in treatment or planning to seek treatment for depression in the next 30 days. Patients receiving the TTM intervention experienced significantly greater symptom reduction during the 9-month follow-up period. The intervention’s largest effects were observed among patients with moderate or severe depression, and who were in the Precontemplation or Contemplation stage of change at baseline. For example, among patients in the Precontemplation or Contemplation stage, rates of reliable and clinically significant improvement in depression were 40% for treatment and 9% for control. Among patients with mild depression, or who were in the Action or Maintenance stage at baseline, the intervention helped prevent disease progression to Major Depression during the follow-up period.[36]

Twelve hundred seventy-seven overweight or moderately obese adults (BMI 25-39.9) were recruited nationally, primarily from large employers. Those randomly assigned to the treatment group received a stage-matched multiple behavior change guide and a series of tailored, individualized interventions for three health behaviors that are crucial to effective weight management: healthy eating (i.e., reducing calorie and dietary fat intake), moderate exercise, and managing emotional distress without eating. Up to three tailored reports (one per behavior) were delivered based on assessments conducted at four time points: baseline, 3, 6, and 9 months. All participants were followed up at 6, 12, and 24 months. Multiple Imputation was used to estimate missing data. Generalized Estimating Equations (GEE) were then used to examine differences between the treatment and comparison groups. At 24 months, those who were in a pre-Action stage for healthy eating at baseline and received treatment were significantly more likely to have reached Action or Maintenance than the comparison group (47.5% vs. 34.3%). The intervention also impacted a related, but untreated behavior: fruit and vegetable consumption. Over 48% of those in the treatment group in a pre-Action stage at baseline progressed to Action or Maintenance for eating at least 5 servings a day of fruit and vegetables as opposed to 39% of the comparison group. Individuals in the treatment group who were in a pre-Action stage for exercise at baseline were also significantly more likely to reach Action or Maintenance (44.9% vs. 38.1%). The treatment also had a significant effect on managing emotional distress without eating, with 49.7% of those in a pre-Action stage at baseline moving to Action or Maintenance versus 30.3% of the comparison group. The groups differed on weight lost at 24 months among those in a pre-action stage for healthy eating and exercise at baseline. Among those in a pre-Action stage for both healthy eating and exercise at baseline, 30% of those randomized to the treatment group lost 5% or more of their body weight vs.18.6% in the comparison group. Coaction of behavior change occurred and was much more pronounced in the treatment group with the treatment group losing significantly more than the comparison group. This study demonstrates the ability of TTM-based tailored feedback to improve healthy eating, exercise, managing emotional distress, and weight on a population basis. The treatment produced the highest population impact to date on multiple health risk behaviors.[37]

Multiple studies have found individualized interventions tailored on the 14 TTM variables for smoking cessation to effectively recruit and retain pre-Action participants and produce long-term abstinence rates within the range of 22% – 26%. These interventions have also consistently outperformed alternative interventions including best-in-class action-oriented self-help programs, [38] non-interactive manual-based programs, and other common interventions.[39][40] Furthermore, these interventions continued to move pre-Action participants to abstinence even after the program ended.[41][42][43]. For a summary of smoking cessation clinical outcomes, see Velicer, Redding, Sun, & Prochaska, 2007.[44]

Important Note: It is important to note that TTM interventions have a significantly greater impact than other programs because of their ability to:

Involve a large percentage of the target population (people not ready, getting ready, or ready to change),

Support high participation rates,

Achieve strong efficacy rates,

Produce multiple behavior changes, and

Use optimal tailoring which minimizes demands on clients and coaches.

For example, out of 1,000 people needing to make a lifestyle change (those in a pre-Action stage), a TTM intervention targets 100% of that population while other programs typically target only the 20% of that population in the Preparation stage. In addition, TTM interventions typically have 70%-80% participation rate with proactive recruitment while other programs typically have a 10% participation rate. Based on the following illustration, TTM interventions clearly have a more substantial impact than action oriented programs even when they share the same efficacy rates.

Target Population

x

Participation Rate

x

Hypothetical Efficacy

=

# of People that Changed Lifestyle

TTM Interventions

1,000 (100%)

x

80%

x

30%

=

240

Other Programs

200 (20%)

x

10%

x

30%

=

30

As you can see in this example, even with the same efficacy rates, a TTM intervention would have 8 times greater impact on the population than another program.

A second systematic review from 2003 asserted that "no strong conclusions" can be drawn about the effectiveness of interventions based on the Transtheoretical Model for the prevention of pregnancy and sexually transmitted diseases.[46]

A 2005 systematic review of 37 randomized controlled trials claimed that "there was limited evidence for the effectiveness of stage-based interventions as a basis for behavior change."[47]

According to a randomized controlled trial published in 2006, a stage-matched intervention for smoking cessation in pregnancy was more effective than a non-stage-matched intervention, but this finding could have resulted from the "greater intensity" of the stage-matched intervention.[48]

A randomized controlled trial published in 2009 found "no evidence" that a smoking cessation intervention based on the transtheoretical model was more effective than a control intervention that was not tailored for stage of change.[49]

A 2009 review stated that "existing data are insufficient for drawing conclusions on the benefits of the Transtheoretical Model" as related to dietary interventions for people with diabetes.[50]

A 2010 systematic review of smoking cessation studies under the auspices of the Cochrane Collaboration found that "stage-based self-help interventions (expert systems and/or tailored materials) and individual counselling were neither more nor less effective than their non-stage-based equivalents."[51]

A 2011 Cochrane Systematic Review found that there is little evidence to suggest that using the Transtheoretical Model Stages of Change (TTM SOC) method is effective in helping obese and overweight people lose weight.[52]

<tr><td style="text-align:left;">Criticism: Little experimental evidence exists to suggest that application of the model is actually associated with changes in health-related behaviors.</td></tr></table>

• In a systematic review of 23 randomized controlled trials published in 2003, the authors reported that "stage based interventions are no more effective than non-stage based interventions or no intervention in changing smoking behaviour."[57]

• A 2005 systematic review of 37 randomized controlled trials claimed that "there was limited evidence for the effectiveness of stage-based interventions as a basis for behavior change."[58]

• A randomized controlled trial published in 2009 found "no evidence" that a smoking cessation intervention based on the Transtheoretical Model was more effective than a control intervention that was not tailored for stage of change.[59]

• The designs of many studies supporting the model have been cross-sectional, but longitudinal study data would allow for stronger causal inferences.[60]

Response:

• A number of longitudinal randomized controlled trials demonstrate that tailored TTM-based interventions do change behaviors.[61][62][63] In fact, the Pro-Change LifeStyle Suite had sufficient longitudinal evidence to be awarded the URAC 2009 Gold Award for Best Practices in Health Management.

• Many studies that show the model to be ineffective have tailored interventions only to stage of change; if the studies had tailored interventions based on all core constructs of the model, they might have shown positive findings.[64] In particular, the "processes of change" have been characterized as "under-researched."[65] A 2007 meta-analysis of tailored print health behavior change interventions found that the "number and type of theoretical concepts tailored on," including stage of change and processes of change, were associated with behavior change (Noar et al., 2007).[66] Hutchison et al. (2008) published a systematic review of 34 articles examining 24 physical activity interventions based on the Transtheoretical Model; only 7 of the 24 interventions addressed all four dimensions "stages of change," "processes of change," "decisional balance," and "self-efficacy."[67]

• Studies that find the model ineffective are poorly designed; for example, they have small sample sizes, poor recruitment rates, or high loss to follow-up.[68][69][70]

• Velicer et al. (2007) examined predictors of smoking cessation at 12 and 24 months among nearly 3000 smokers from 5 randomized effectiveness trials. They reported that stage was of the strongest predictors of smoking status at 12 and 24 months, refuting the claim that stage of change is descriptive rather than predictive.[71]

<tr><td style="text-align:left;">Criticism: "Arbitrary dividing lines" are drawn between the stages.[72]</td></tr></table>

Response: The conversion of continuous data into discrete categories is necessary for the model, similar to how decisions are made about the treatment of high cholesterol levels depending on the discrete category the cholesterol level is placed into.[73]

<tr><td style="text-align:left;">Criticism: The model makes predictions that are "incorrect or worse than competing theories."[74]</td></tr></table>

Response: Velicer at al. (1999) conducted a study to examine the validity of 40 predictions based on the Transtheoretical Model regarding movement from one of three initial stages (Precontemplation, Contemplation, or Preparation) to stage membership 12 months later. Thirty-six predictions were confirmed in these longitudinal analyses.[75]

<tr><td style="text-align:left;">Criticism: In a 2002 review, the model's stages were characterized as "not mutually exclusive"; furthermore, there was "scant evidence of sequential movement through discrete stages." [76].</td></tr></table>

Response: The TTM does not suggest that movement through the stages is always linear. Latent transition analyses on data from effectiveness trials of tailored interventions (e.g., Martin, Velicer, & Fava, 1996) reveal that movement through the stages is not always linear, that the probability of forward stage movement is greater than the probability of backward stage movement, and that the probability of adjacent stage movement is greater than the probability of two-stage progression.[77]

• The interventions included in the review are treated as comparable even though they differ dramatically on which TTM variables are used for tailoring, length of follow-up, sample size, percentage of eligible smokers recruited, and intervention modalities used. Based on our analysis, approximately 60% of the studies in Spencer et al. (2002) and 70% in Riemsma et al. (2003) used only the stage variable from the TTM. Tailoring only on stage is the most common application of the TTM. Five studies in Spencer et al., and three in Riemsma et al., tested interventions tailored on a partial set of TTM variables, namely stage, decisional balance, and/or self-efficacy. Five studies in Spencer et al. and four in Riemsma et al. tested interventions tailored on the full set of TTM variables, including processes of change.

• To assume that tailoring simply on stage would be TTM-based is analogous to assuming that tailoring simply on self-efficacy is based on social cognitive theory. In both situations, important theoretical constructs are not being used, and an important percentage of variance is not being accounted for or controlled. From a practical perspective, it could mean that the only tailored information specific to an individual is based on a single variable. All other information must be general information that has to be assumed to be valid for all people in a particular stage. However, theory and data both contradict this assumption, as individuals in a particular stage, such as Precontemplation, are theoretically expected and have been empirically demonstrated to differ on key TTM variables like the pros and cons of changing and experiential processes of change.

• If effective tailoring requires feedback that is accurate for individuals, then tailoring on stage alone should be less effective than tailoring on a larger set of TTM variables. Of 13 studies in Spencer et al. (2002) and 16 in Riemsma et al. (2003) that used the single variable of stage, only 10 had positive results (about 35%). Of the eight that applied partial TTM tailoring, four (50%) had significant effects. Finally, of the seven studies that applied full tailoring, five (about 70%) had significant effects. The two fully tailored studies that were negative involved teenagers. The number of fully tailored TTM studies was relatively small, but the number of smokers studied was large (>10,000).

• The impact of fully tailored TTM interventions for smoking has been repeatedly demonstrated in randomized, population-based studies with diverse populations since Riesma et al.(2003). These studies tended to produce the same magnitude of effects at long-term follow-up (22% to 26% point-prevalence abstinence), as was found in our first sample of convenience,[80] a representative sample of 5130 smokers,[81] and an HMO population of 4653 smokers.[82] Similar abstinence rates (23.9%) have been found when treating a population of adolescents in primary care.[83] Hall et al., 2006 reported comparable results in a population of smokers being treated for depression.[84] With pregnant smokers in the UK, adding a TTM-tailored intervention to the traditional treatment of midwife counseling produced more than eight times the impact compared to the traditional treatment alone.[85][86]

• Recent research demonstrated the same range of abstinence when treating populations with TTM fully tailored interventions for multiple behaviors. This was the case with a population of 2460 parents of teenagers who were treated for three behaviors.[87] The significant abstinence rate was 22.9% with an even higher success for those progressing from high-fat to low-fat diets (38.2%) and for those progressing from high-risk to low-risk ultraviolet (UV) exposure (35.2%). Similar results were produced with a population of 5545 primary care patients (Prochaska et al. 2005). Long-term significant abstinence was 25.6% with even greater success for diet and sun exposure. Such studies are causing us to change traditional impact equations from (impact = participation rate x efficacy) to (impact = participation rate x efficacy x number of behaviors changed).

<tr><td style="text-align:left;">Criticism: On Wednesday, October 5th, 2011, Cochrane published a narrative review of five studies by Tuah, Amiel, Qureshi, Car, Kaur, and Majeed that claimed to assess the effectiveness of dietary and physical activity interventions based on the Transtheoretical Model of behavior change (TTM) to produce sustainable weight loss in overweight and obese adults. The review included a series of serious flaws that call into question the validity of the conclusions drawn.</td></tr></table>

Response:
The authors claimed to be studying the impact of TTM-based interventions on weight loss and reported that the selection criteria included randomized controlled trials using the "TTM SOC as a model, theoretical framework, or guideline in designing lifestyle modification strategies (mainly dietary and physical activity versus a comparison intervention of usual care). One of the outcome measures of the study was weight loss, and participants were overweight and obese adults." These criteria, however, were not systematically applied. Most glaringly, two of the five trials (Dinger et al., 2007 & Steptoe et al., 2001) did not include weight loss as an outcome. Furthermore, those two studies included participants who were not overweight or obese. Jones et al., (2003) included no physical activity intervention and measured weight only as a secondary outcome. That leaves two studies that potentially met the inclusion criteria. A careful reading of Logue et al. (2005), however, indicates that behavior change targets were not clearly specified in that intervention, which the authors defined as a "minimal intervention for obesity." Rather than using public health criteria for reaching Action for diet and physical activity, Logue et al. (2005) reported focusing on small, non-specific increases in exercise and eating.

Though the stated outcome of the review was to assess the potential for TTM-based interventions to measure sustained weight loss, sustainability of weight loss was not adequately assessed. Of the three studies that measured weight loss, two of the three (Jones et al., 2003 and Logue et al., 2005) measured weight loss only at the end of treatment. No follow-up beyond the end of treatment was included. Only one of five studies measured weight loss at one year post-intervention (Johnson et al., 2008). When examined carefully, the results of this study demonstrate that in the context of a truly effective, evidence-based TTM individualized intervention, weight loss in the treatment and control groups begins to diverge at 24 months (a full 12 months after treatment ended). In fact, Johnson et al. (2008) reported that among participants in the pre-action stages (i.e., those at risk for diet and/or physical activity), there was a significant and increasing difference over time in the proportion of participants losing at least 5% of their body weight. At the 24-month follow-up, 30% of those in a pre-action stage for both healthy eating and exercise at baseline had lost at least 5% of their body weight in the treatment group versus only 18.6% of the comparison group.

The bar for being defined as TTM-based intervention study was set far too low. The authors note that listing stage names "fulfills criteria for using TTM SOC." The only thing common to the included studies, however, is that SOC names appeared in the abstracts. As the authors acknowledge, the TTM was inconsistently applied in everything from one size fits all email reminders (improperly using primarily behavioral processes of change for a sample almost entirely in Contemplation at pre-test) in an under-powered 6-week long study with no follow-up in which weight wasn’t even measured (Dinger et al., 2007) to stage-matched messages in 2-3 interactions from a nurse with only brief training (Steptoe et al., 2001), to weight loss advisors who adhered to the intervention protocol less than 50% of the time (Logue et al., 2005). Investigators with adequate knowledge of the TTM recognize that it is a comprehensive model of behavior change in which stage of change is one of 14 variables that make up the model. To date, the best practices for TTM-based interventions employ statistical decision making to derive evidence-based decision rules about how to best match messages to a participant’s readiness to change and status on multiple behavior change variables. Conclusions regarding the efficacy and effectiveness of TTM-based interventions should be based on high quality research that applies the model appropriately, just as conclusions about the efficacy of medications are based on well controlled trials of pharmacologic agents manufactured under the strictest quality controlled procedures. Unfortunately, those standards were not applied here.

The review gave no consideration to the quality of studies included beyond the reporting of potential biases that were often, as the authors admitted, inappropriate for consideration for the trials included. No mention, for example, was made about whether the studies reviewed had adequate statistical power.

The following notes summarize major differences between the well-known 1983,[14] 1992,[22] and 1997[25] versions of the model. Other published versions may contain other differences. For example, Prochaska, Prochaska, and Levesque (2001)[26] do not mention the Termination stage, Self-efficacy, or Temptation.

↑In the 1983 version of the model, the Termination stage is absent. In the 1992 version of the model, Prochaska et al. showed Termination as the end of their "Spiral Model of the Stages of Change," not as a separate stage.

↑In the 1983 version of the model, Relapse is considered one of the five stages of change.

↑In the 1983 version of the model, the processes of change were said to be emphasized in only the Contemplation, Action, and Maintenance stages.

↑In the 1983 version of the model, "decisional balance" is absent. In the 1992 version of the model, Prochaska et al. mention "decisional balance" but in only one sentence under the "key transtheoretical concept" of "processes of change."

↑In the 1983 version of the model, "self-efficacy" is absent. In the 1992 version of the model, Prochaska et al. mention "self-efficacy" but in only one sentence under the "key transtheoretical concept" of "stages of change."

↑Prochaska, JO; Norcross, JC; DiClemente, CC. Changing for good: the revolutionary program that explains the six stages of change and teaches you how to free yourself from bad habits. New York: W. Morrow; 1994. ISBN 0-688-11263-3.

↑Miller, Kay. Revolving resolutions - Year after new year, we vow to lose weight, stop smoking, find love or a better job -- only to fail. A few simple strategies could set us straight. Star Tribune: Newspaper of the Twin Cities 2001 Dec 29.

↑ Prochaska, JO; Norcross, JC; DiClemente, CC. Changing for good: the revolutionary program that explains the six stages of change and teaches you how to free yourself from bad habits. New York: W. Morrow; 1994. ISBN 0-688-11263-3.

Pro-Change Behavior Systems, Inc. Company founded by James O. Prochaska. Mission is to enhance the well-being of individuals and organizations through the scientific development and dissemination of Transtheoretical Model based change management programs.